Method of constructing secondary members for induction-motors



. I. H. MILLS.

METHOD OF CONSTRUCTING SECONDARY MEMBERS FOR INDUCTION MOTORS.

4 APPLICATION FILED MAR. 19, 1919.

1,371,570. Patented Mar. 15,1921.

WITNESSES: INVENTOR Kama u I Isaac hf Mil/s UNITED STATES PATENT OFFICE.

ISAAC H. MILLS, OF TURTLE CREEK, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

' METHOD OF CONSTRUCTING SECONDARY MEMBERS FOR INDUCTION-MOTORS.

Specification of Letters Patent.

Patented Mar. 15, 1921.

Original application filed December 13, 1917, Serial No. 206,868. Divided and this application filed March 19, 1919. Serial No. 283,506.

'1 0 all whom it may concern:

Be it known that I, ISAAC H.1.-MILLS, a citizen of the United States, and a"resident of Turtle Creek, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Methods of Constructing Secondary Members for In duction-Motors, of which the following is a specification.

My invention relates to the.construct1on of secondary members for induction motors and particularly to the construction of windings for secondary members of the squirrel-cage type and to damping windings and amortisseur windings for dynamo-electric machines.

This application is a division of my application, Serial No. 206,868, filed Dec. 13, 1917, and assigned to the Westinghouse Electric & Manufacturing Company.

One object of my invention is to provide a process of manufacturing members of the above-indicated class which shall greatly reduce the cost of such parts and improve their construction.

A further object of my invention is to provide a structure that shall not require skilled workmen for assembling the same.

In the construction of windings of the types under discussion, it is customary practice to provide saw-cuts in the ends of the inductor bars and to secure the bars to the resistor rings by expanding these cuts and bending the material at the sides thereof in opposite directions. This operation requires a considerable degree of skill for its proper accomplishment, and the windings thus constructed are not uniform in appearance or in operation.

In accordance with my invention, I provide a bending and rolling process which is applicable to split inductors for securing the inductor bars of squirrel-cage rotors to the resistance-rings. 45 t Figure 1 of the accompanying drawing is a view, in perspective, of a secondary member of an inductor'motor being constructed in accordance with my invention; Fig. 2 is a side elevational view of a tool employed for flattening the ends of the inductor bars; Fig. 3 is a view, partially in side elevation, and partially in section, of the apparatus used in bending the inductor-bar ends; Fig. f4.- 1s a similar view illustrating a later step in the process; and Fig. 5 is an end view of a portion of a rotor resulting from this process.

The squirrel-cage secondary member of the induction motor that is illustrated in the drawing comprises two conducting, but preferably non-magnetizable, end plates 1 and intermediate magnetizable core punchings or laminae 2 which are provided with slots adjacent to their peripheries for the reception of inductor bars 3. The end portions of the inductor bars 3 extend somewhat beyond the end plates 1, when initially assembled, but are subsequently bent down by a tool 16 and flattened by a roller 4 which is applied, under pressure, to the ends of the bars 3 in order to bend the same and to securely clamp the core punchings 2 between the end plates 1.

When the inductor bars are initially positioned in the core slots, certain of the bars have ends projecting a short distance beyond the end plates 1, as illustrated by the bars 5 of Fig. 1. The secondary member, thus assembled, is placed upon a support and the tool 16 is used to bend the end portions, as shown at 6 in Fig. 1, after which the roller 4 is rolled over the ends of the bars, ,under considerable pressure, to flatten the same, as shown at 7 (Fig. l). The member is then inverted and the same process applied to the other ends of the bars.

The roller 4, by means of which the fiattening process is accomplished, together with its associated support, is shown in Fig. 2 of the drawing. A tapered shank 8 is adapted to be received in the chuck of a drill press, or other apparatus for producing rotation thereof, and is provided with a cross-head 9 upon which the roller arm 10 is adjustably mounted. The roller 4 is rotatably mounted on the arm 10 and is adapted to be revolved by the rotation of the shank 8. r

Figs. 3, 4 and 5 are detail views of apparatus employed in my invention and showing the split inductor 3 composed of two separate portions placed in the armature slots from opposite ends. As assembled,

each portion has one end bent to constitute shoulder 15 and the other end is bent over by the tool it the roiier 4: after the bars are assembied in place. One arm 9 of a tool, such as that shown in 2, may be pro v L631 as topl. 16 which may be p vot u "27 and be heir? 3 ing position u stop is pr vi led on the arm 1 After the ends or some or all of the bars at one end of the rotor have been partially bent over by means of the tool 16, the roller 4 may be applied to the bent-over ends, under considerable pressure, to force them into engagement with the end plate 1. If the ends of all of the bars 5 are bent over before the roller 4 is put into service, the stop 18 may then be withdrawn and the tool 16 turned about its pivot 17 to an inoperative position. The flat-faced roller 4, which may be carried on another arm ofthe tool shown in Fig. 2 may then be applied, under pressure, to the partially bent tips of the inductor bars 3 in order to press the same into close engagement with the end ring.

Although I have described my invention as applied to the construction of secondary members of induction motors, it is obviously not so limited but may be used forenlarging the heads of any series of elongated members or for expanding the protruding ends of divided rivets. I desire, therefore, that only such limitations shall be imposed as are set forth in the appended claims.

I claim as my invention:

1. The method of constructing a squirrelcage rotor which consists in assembling an end plate and a plurality of elongated conductors in such relation that the ends of said conductors project through spaced openings in said end plate, applying a force to said end portions substantially normal'thereto to bend the same, and subsequently passing a roiler thereover to ress them engage ment H retired constructing a strait-rel= cage rotor which consists "n k urality of eiongated con -n spaced side-by-side relation between two end rings and having end portions protruding there through, rotating a member a piano substantially parailel to the end plate to the said protruding end portions and subsequently moving a roller over said end portions to bend them into engagement with the end plate.

3. The method of constructing a squirrelcage rotor which consists in assembling a plurality of elongated conductors inspaced side-by-side i'elation between two end plates and having end portions protruding therethrough, disposing said rotor so that the protruding end portions of the bars are all in the path of a rotating bending member and subsequently rotating a roller so as to mash the bended conductor end portions into engagement with the end plate.

4. The method of constructing a squirrelcage rotor whichconsists in assembling a plurality of elongated conductors in spaced side-by-side relation between two end plates and having end portions protruding therethrough, disposing said rotor so that the protruding end portions of the bars are all in the path of a rotating bending member and subsequently rotating a roller so as to mash the bended conductor end portions into engagement with the end plate, said roller being rotated in the same direction as was the bending member.

in testimony whereof, I have hereunto subscribed my name this 7th day of March,

ISAAC H. MILLS. 

